Setting: ED
CC: “My stool is black.”
VS: BP: 96/56 mm Hg; P: 108 beats/minute; T: 98.8°F; R: 22 breaths/minute
HPI: A 76-year-old man with a history of aortic stenosis (AS) comes with 3 days of multiple red, black stools. He had five episodes just today. He is dyspneic on exertion and comes now because of tiredness.
PMHX:
AS
Hypertension
Former tobacco smoker
Hyperlipidemia
Medications:
Atorvastatin
Nifedipine
PE:
Cardiovascular: 3/6 murmur radiating to carotid arteries
Abdomen: soft, nontender
What is the most important first step to take with this patient?
a. Check for orthostasis.
b. Start normal saline (NS) bolus.
c. Order a colonoscopy.
d. Order an upper endoscopy.
Answer b. Start normal saline (NS) bolus.
Fluid resuscitation is by far the most important thing you can do for a person with a large gastrointestinal (GI) tract bleed. It is far more important to restore perfusion pressure than to look for the precise etiology of the bleed. Also, a tachycardia (pulse rate >100 beats/minute) at rest or systolic blood pressure (SBP) <100 mm Hg indicates a 30% blood volume loss. For an average-sized person, this is 1.5 to 2 L of volume lost. Orthostasis implies the loss of about 15% to 20% of blood volume. This person’s current blood pressure (BP) (96/56 mm Hg) and pulse rate (108 beats/minute) imply that more volume has been lost than would occur with mere orthostasis. When intravascular volume is low, there should be an increase in heart rate and a vasoconstriction of peripheral vessels to fully correct BP.
Orthostasis:
Check BP and pulse rate when the patient is laying down, then sitting up or standing:
• Increase in pulse rate >10 beats/minute
• Decrease in systolic BP >20 mm Hg
Orthostasis: 15% to 20% volume lost
SBP <100 mm Hg or pulse rate >100 beats/minute = 30% blood volume lost
Orthostasis is detected by:
• Decreased firing of mechanoreceptors
• Carotid, aortic arch
Where is the information processed that detects decreased firing of carotid and aortic baroreceptors resulting in vasoconstriction and tachycardia?
a. Frontal lobes
b. Medulla oblongata
c. Hypothalamus
d. Thalamus
e. Internal capsule
Answer b. Medulla oblongata
The medulla receives information from the stretch or mechanoreceptors of the carotid artery, atria, and aortic arch. Decreased pressure in peripheral pressure or mechanoreceptors results in decreased firing. The medulla will respond with a peripheral vasoconstriction and tachycardia. Norepinephrine will stimulate alpha-1-receptors in arterioles causing vasoconstriction. This compensation is incomplete when changing position if there is >15% to 20% blood volume loss.
Initial Orders:
NS or Ringer lactate bolus
Complete blood count (CBC), prothrombin time (PT), activated partial thromboplastin time (aPTT), type and cross, CHEM-20
Electrocardiogram (ECG)
Pantoprazole IV
GI consult
Move the clock forward 15 minutes and recheck both blood pressure and pulse rate. If the SBP is <100 mm Hg, reorder a bolus of intravenous (IV) NS. If after two boluses, the SBP is still low, transfer the patient to the intensive care unit (ICU).
On the computer-based case simulation (CCS), the consultant does not tell you what to do, but in this case, getting a GI consultation implies you know they are needed for serious GI tract bleeding.
Report:
CBC: hematocrit 32%; mean corpuscular volume (MCV) 82 fL; platelets 185,000/μL
PT, aPTT: normal
Chemistry: blood urea nitrogen (BUN) 32 g/dL (elevated); creatinine 1.1 mg/dL
ECG: no ST-T or T-wave abnormalities
The first CBC is not accurate in acute bleeding. You must always repeat it to see the trend.
If the PT or aPTT is prolonged (elevated), what is the best way to correct it?
a. Fresh frozen plasma (FFP)
b. Vitamin K orally
c. Vitamin K IV
d. Cryoprecipitate
Answer a. Fresh frozen plasma (FFP)
The fastest way to correct a coagulopathy is with FFP. Vitamin K needs at least 12 to 24 hours to work in order to generate clotting factors. If there is liver insufficiency, then FFP will not work at all. Cryoprecipitate is a condensation of clotting factors from pooled multiple donors. You will collect 50% of the clotting factors in 10% of the volume of fluid. Cryoprecipitate is best when you need enormous amounts of clotting factors and FFP is not enough or the volume of FFP required to provide that amount of clotting factor would be too great.
Which of the following is in highest concentration in cryoprecipitate?
a. Fibrinogen, von Willebrand factor
b. Factor II, VII
c. Factor XI, X
d. Factor XII
Answer a. Fibrinogen, von Willebrand factor
Cryoprecipitate is especially high in fibrinogen, von Willebrand factor (vWF) and factor VIII. The reason we never use cryoprecipitate first for anyone is that we use desmopressin acetate (DDAVP) for vWF and recombinant factor VIII for hemophilia and those with von Willebrand disease (vWD) not responding to DDAVP.
Cryoprecipitate is a pooled product.
Pooled products transmit more viruses.
The patient’s repeat BP is 100/64 mm Hg and pulse rate is 102 beats/minute.
Orders:
Bolus NS
CBC
BUN level rises with decreased renal perfusion or prerenal azotemia.
Why does the BUN level rise in prerenal azotemia?
a. Angiotensin breaks down proteins.
b. Catecholamine release breaks down proteins.
c. Antidiuretic hormone (ADH) increases urea absorption at the collecting duct.
d. ADH decreases urea excretion at proximal tubule.
Answer c. Antidiuretic hormone (ADH) increases urea absorption at the collecting duct.
When ADH increases the permeability of the collecting duct to water, it also stimulates urea transporters that increase urea reabsorption. This helps maintain the high osmolarity of the renal medulla so that water can be reabsorbed. Although urea is a metabolic end product of protein metabolism, neither angiotensin nor catecholamines has any effect on protein production or destruction. Angiotensin does increase urea levels.
ADH stimulates UT1 or “urea transporter 1” in the collecting duct to absorb urea.
More ADH = More Urea Reabsorbed
Blood in the upper GI tract increases BUN level.
With major GI tract bleeding, move the clock forward 15 to 30 minutes. IV fluids and proton pump inhibitors (PPIs) should be running continuously.
Which therapy has a definite benefit in acute upper GI tract bleeding?
a. PPI
b. H2-blocker
c. Sucralfate
d. Nasogastric tube
e. Iced saline lavage
Answer a. PPI
PPIs do have a benefit in stopping and controlling acute upper GI tract bleeding. This has never been shown with the H2-blockers or sucralfate. The nasogastric (NG) tube has extremely little benefit. There is no therapeutic intervention with an NG tube. The iced saline lavage is useless.
Move the clock forward to get CBC results:
The repeat CBC shows hematocrit level at 29% and platelet count at 165,000/μL.
What mechanism explains the drop in hematocrit concentration from 32% to 29% in this patient?
a. Continued upper GI tract blood loss
b. Continued lower GI tract blood loss
c. Dilution from hydration
Answer c. Dilution from hydration
It is expected that patients will have a decrease of 3 to 4 points in hematocrit concentration just from hydration of fluids. You should only consider a decrease more than this amount to be significant.
Black Stool or Melena = Upper GI Tract Source
Upper GI Tract Source = Proximal to Ligament of Treitz
Which of the following is a definite benefit of an NG tube?
a. Decreases mortality
b. Can help determine source of bleeding
c. Stops rate of blood loss
d. Eliminates need for endoscopy
Answer b. Can help determine source of bleeding
If you are going to do upper endoscopy in a patient, NG tube placement is useless and painful. If you do not know whether to scope from above or below, an NG tube is occasionally useful to help localize the source of bleeding to the upper GI tract. The problem with the NG tube, besides its discomfort, is that a negative lavage misses 30% of bleeding especially if it is in the duodenum. Red blood from the NG tube indicates an upper GI tract source. Only the use of an NG tube definitively excludes an upper GI tract source if you see bile in the aspirate.
An NG tube misses 30% of upper GI tract bleeds.
A CBC after 2 hours of hydration shows the following:
Hematocrit 23%
Platelets 145,000/μL
What would be the likely cause of death in a patient with GI tract bleeding?
a. Stroke
b. Myocardial infarction
c. Congestive heart failure (CHF)
d. High output cardiac failure
e. Renal failure
Answer b. Myocardial infarction
Decreased oxygen-carrying capacity to the myocardium leads to ischemia. Myocytes in the heart cannot distinguish between hypoxia, coronary stenosis, or anemia. Ultimately, with severe bleeding and anemia, the patient will infarct his heart. This patient has AS. That implies a 50% to 70% chance of coronary disease as well. An older person needs to keep the hematocrit concentration >25% to 30%. A young, healthy person can easily tolerate a hematocrit level of 20% or 25% until his or her bone marrow recovers in 2 to 3 weeks.
Older people or those with coronary disease die at hematocrit levels that just make a younger person tired.
After several hours, do an “Interval History.” Also do an Interval History if there is a change in laboratory values such as this drop in hematocrit concentration.
The patient reports feeling light-headed and short of breath. This is an absolute indication for transfusion in addition to a dropping blood count on CBC.
Orders:
Packed red blood cells
CBC
Upper endoscopy
Hematocrit should increase by 3 points for each unit of packed red blood cells given.
On CCS, treatments like transfusion are considered done or “administered” immediately, but you cannot detect the effects of them until after you move the clock forward and get a repeat test.
After an hour post transfusion, you repeat the CBC and see the following:
Hematocrit: 25%
Platelets: 132,000/μL
At what platelet count should you order a platelet transfusion?
a. <150,000/μL
b. <100,000/μL
c. <50,000/μL
d. <10,000/μL
Answer c. <50,000/μL
Give platelets when the level drops below 50,000/μL when patients are bleeding or going for surgery. If a patient is not bleeding, you never need to keep the count that high.
Death from GI tract bleed is from inadequate fluid resuscitation.
The upper endoscopy was performed and no varices were found, but there is an ulcer in the duodenum with a visible bleeding vessel. The vessel was injected with epinephrine and electrical diathermy or cautery was applied and the bleeding has ceased.
What would be done differently if there were esophageal varices?
a. Octreotide and banding
b. Octreotide and sclerotherapy
c. Propranolol
d. Blakemore tube
e. Surgical shunt
f. Transjugular intrahepatic portosystemic shunt (TIPS)
Answer a. Octreotide and banding
Octreotide decreases acute variceal bleeding. Banding stops bleeding vessels. Sclerotherapy is only done if banding cannot be performed for a technical reason. Sclerotherapy has far greater risk of ulceration and stricture later. Propranolol prevents subsequent bleeding. Beta-blockers have no effect in acute GI tract bleeding.
A Blakemore tube is rarely ever used. It is a temporary procedure to tamponade bleeding vessels until surgery or the TIPS procedure can be done.
Octreotide is a somatostatin.
Somatostatin decreases portal hypertension.
After the procedure, repeat the CBC several times every few hours. Continue the PPI. When the CBC shows the hematocrit level has stabilized, the patient can be transferred out of the ICU.